A method of forming a feature in a stack comprising a dielectric material on a substrate is provided. An etch plasma is generated from an etch gas, exposing the stack to the etch plasma and partially etching the feature in the stack. The stack is primed. A protective film is deposited on sidewalls of the feature by repeating for a plurality of cycles the steps of exposing the stack to a first reactant, allowing the first reactant to adsorb onto the stack, and exposing the stack to a second reactant, wherein the first and second reactants react with one another to form the protective film over the stack. The etching, priming, and depositing a protective film are repeated until the feature is etched to a final depth.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A method of forming a feature in a stack comprising a dielectric material on a substrate, the method comprising: (a) generating an etch plasma from an etch gas, exposing the stack to the etch plasma, and partially etching the feature in the stack; (b) after (a), priming the stack; (c) depositing a protective film on sidewalls of the feature by (i) exposing the stack to a first reactant and allowing the first reactant to adsorb onto the stack, (ii) exposing the stack to a second reactant, wherein the first and second reactants react with one another to form the protective film over the stack, and (iii) repeating (i) and (ii) in a cyclic manner a plurality of times; and (d) repeating (a)-(c) until the feature is etched to a final depth, wherein the generating the etch plasma is performed while cooling the substrate to a temperature below −20° C., and wherein the depositing the protective film is performed while heating the substrate to a temperature above 20° C.
2. The method, as recited in claim 1 , wherein the priming the stack modifies surfaces of the sidewalls to better facilitate the depositing the protective film.
3. The method, as recited in claim 2 , wherein the priming the stack comprises at least one of an oxidizing plasma to remove some sidewall etch residue, a reducing plasma to remove some sidewall etch residue, or a non-plasma vapor treatment to functionalize a surface of the stack.
4. The method, as recited in claim 1 , wherein the priming the stack comprises providing an oxidizing plasma, comprising: providing an oxidizing gas comprising at least one of O 2 , N 2 , CO 2 , NF 3 , SF 6 , H 2 O, and COS; and forming a plasma from the oxidizing gas.
5. The method, as recited in claim 1 , wherein the priming the stack comprises providing a reducing plasma, comprising: providing a reducing gas comprising at least one of H 2 , a mixture of N 2 +H 2 , N 2 H 4 , and NH 3 ; and forming a plasma from the reducing gas.
6. The method, as recited in claim 1 , wherein the priming the stack comprises providing a non-plasma vapor treatment to functionalize a surface of the stack, comprising exposing the surface of the stack to a vapor of at least one of H 2 O, NH 3 , O 3 , N 2 H 4 , or H 2 O 2 .
7. The method, as recited in claim 1 , further comprising curing the protective film, wherein the curing the protective film is effected by at least one of visible or UV light irradiation, infrared irradiation, or exposure to a curing plasma.
8. The method, as recited in claim 1 , wherein the protective film comprises at least one of a metal, sulfur, boron, silicon, nitrogen, or phosphorous.
9. The method, as recited in claim 1 , further comprising performing a breakthrough etch to etch the protective film at neck locations.
10. A method of forming a feature in a stack comprising a dielectric material on a substrate, the method comprising: (a) generating an etch plasma from an etch gas, exposing the stack to the etch plasma, and partially etching the feature in the stack; (b) after (a), depositing a protective film on sidewalls of the feature by (i) exposing the stack to a first reactant and allowing the first reactant to adsorb onto the stack, (ii) exposing the stack to a second reactant, wherein the first and second reactants react with one another to form the protective film over the stack, and (iii) repeating (i) and (ii) in a cyclic manner a plurality of times; (c) curing the protective film; and (d) repeating (a)-(c) until the feature is etched to a final depth, wherein the generating the etch plasma is performed while cooling the substrate to a temperature below −20° C., and wherein the depositing the protective film is performed while heating the substrate to a temperature above 20° C.
11. The method, as recited in claim 10 , wherein the curing the protective film is effected by at least one of visible or UV light irradiation, infrared irradiation, or exposure to a curing plasma.
12. The method, as recited in claim 10 , wherein the curing the protective film creates cross-links in a polymer forming the protective film.
13. The method, as recited in claim 10 , wherein the curing the protective film removes some hydrogen content of the protective film to increase the graphitic or carbidic nature of the protective film.
14. The method, as recited in claim 10 , wherein the curing the protective film densifies the protective film.
15. The method, as recited in claim 10 , wherein the curing the protective film is a step in each cycle of the depositing the protective film.
16. The method, as recited in claim 10 , wherein the protective film comprises at least one of a metal, sulfur, boron, silicon, nitrogen, or phosphorous.
17. The method, as recited in claim 10 , further comprising performing a breakthrough etch to etch the protective film at neck locations.
18. A method of forming a feature in a stack comprising a dielectric material on a substrate, the method comprising: (a) generating an etch plasma from an etch gas, exposing the stack to the etch plasma, and partially etching the feature in the stack; (b) after (a), depositing a protective film on sidewalls of the feature by (i) exposing the stack to a first reactant and allowing the first reactant to adsorb onto the stack, (ii) exposing the stack to a second reactant, wherein the first and second reactants react with one another to form the protective film over the stack, wherein the protective film comprises at least one of a sulfur, boron, silicon, nitrogen, or phosphorous, and (iii) repeating (i) and (ii) in a cyclic manner a plurality of times; and (c) repeating (a)-(b) until the feature is etched to a final depth, wherein the generating the etch plasma is performed while cooling the substrate to a temperature below −20° C., and wherein the depositing the protective film is performed while heating the substrate to a temperature above 20° C.
19. The method, as recited in claim 18 , wherein the protective film further comprises at least one of aluminum (Al), titanium (Ti), tungsten (W), tantalum (Ta), hafnium (Hf), or ruthenium (Ru).
20. The method, as recited in claim 18 , further comprising performing a breakthrough etch to etch the protective film at neck locations.
21. A method of forming a feature in a stack comprising a dielectric material on a substrate, the method comprising: (a) generating an etch plasma from an etch gas, exposing the stack to the etch plasma, and partially etching the feature in the stack; (b) after (a), depositing a protective film on sidewalls of the feature by (i) exposing the stack to a first reactant and allowing the first reactant to adsorb onto the stack, (ii) exposing the stack to a second reactant, wherein the first and second reactants react with one another to form the protective film over the stack, and (iii) repeating (i) and (ii) in a cyclic manner a plurality of times; (c) performing a breakthrough etch to etch the protective film at neck locations; and (d) repeating (a)-(c) until the feature is etched to a final depth, wherein the generating the etch plasma is performed while cooling the substrate to a temperature below −20° C., and wherein the depositing the protective film is performed while heating the substrate to a temperature above 20° C.
22. The method, as recited in claim 21 , wherein the performing the breakthrough etch comprises exposing the stack to a plasma comprising oxygen.
23. The method, as recited in claim 21 , wherein the performing the breakthrough etch completely removes the protective film on the etch fronts without completely removing the protective film on the sidewalls of the feature.
24. A method of forming a feature in a stack comprising a dielectric material on a substrate, the method comprising: (a) generating an etch plasma from an etch gas, exposing the stack to the etch plasma, and partially etching the feature in the stack, while cooling the substrate to a temperature below −20° C.; (b) after (a), depositing a protective film on sidewalls of the feature at a temperature of at least 20° C. by (i) exposing the stack to a first reactant and allowing the first reactant to adsorb onto the stack, (ii) exposing the stack to a second reactant, wherein the first and second reactants react with one another to form the protective film over the stack, and (iii) repeating (i) and (ii) in a cyclic manner a plurality of times; and (c) repeating (a)-(b) until the feature is etched to a final depth.
25. The method, as recited in claim 24 , wherein the etch gas comprises H 2 and at least one of a fluorocarbon or hydrofluorocarbon.
26. A method of forming a feature in a stack comprising a dielectric material on a substrate, the method comprising: (a) generating an etch plasma from an etch gas, exposing the stack to the etch plasma, and partially etching the feature in the stack, wherein the generating the etch plasma is performed while cooling the substrate to a temperature below −20° C.; (b) after (a), depositing a protective film on sidewalls of the feature by (i) exposing the stack to a first reactant and allowing the first reactant to adsorb onto the stack, (ii) exposing the stack to a second reactant, wherein the first and second reactants react with one another to form the protective film over the stack, wherein the protective film comprises at least one of a sulfur, boron, silicon, nitrogen, or phosphorous, and (iii) repeating (i) and (ii) in a cyclic manner a plurality of times; and (c) repeating (a)-(b) until the feature is etched to a final depth.
27. A method of forming a feature in a stack comprising a dielectric material on a substrate, the method comprising: (a) generating an etch plasma from an etch gas, exposing the stack to the etch plasma, and partially etching the feature in the stack, wherein the generating the etch plasma is performed while cooling the substrate to a cryogenic temperature below −20° C.; (b) after (a), depositing a protective film on sidewalls of the feature by (i) exposing the stack to a first reactant and allowing the first reactant to adsorb onto the stack, (ii) exposing the stack to a second reactant, wherein the first and second reactants react with one another to form the protective film over the stack, wherein the protective film comprises at least one of a sulfur, boron, silicon, nitrogen, or phosphorous, and (iii) repeating (i) and (ii) in a cyclic manner a plurality of times; and (c) repeating (a)-(b) until the feature is etched to a final depth, wherein the depositing the protective film is performed while heating the substrate to a non-cryogenic temperature.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
August 21, 2018
November 9, 2021
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